<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>

    <style>
      /* CSS样式 */
      h1 {
        color: red;
        /* 字体大小：14像素 */
        font-size: 14px;
        border: 1px solid red;
      }
    </style>
  </head>
  <body>
    <h1>我是h1标签</h1>

    <p>我是p标签</p>
  </body>
</html>
